Apparatus and method of managing hidden area

• US 7,861,311 B2
• Filed: 01/09/2007
• Issued: 12/28/2010
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Seo, Dong-young, Kwon, Moon-sang, Shin, Hee-sub
• Primary Examiner(s): Homayounmehr; Farid
• Assistant Examiner(s): Durham; Imhotep
• Application Number:
  US11/650,941
• Publication Number:
  US 20070180535A1
• Time in Patent Office: 1,449 Days
• Field of Search: 711/159, 711/161, 711/163, 713/165, 713/164, 707/102, 707/200, 707/204, 707821-823, 707828-830
• US Class Current: 726/27
• CPC Class Codes: G06F 16/16 File or folder operations, e.g. details of user interfaces specifically adapted to file systems
• CPC Class Codes: G06F 21/6281 at program execution time, where the protection is within the operating system
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00

Abstract

Provided is a method of hiding a specified directory with no effect on compatibility with an existing file system. According to an aspect of the invention, an apparatus for managing a hidden area includes a hidden area generation unit which sets a portion of the data area as a hidden area and records meta data for the set hidden area, a hidden area release unit which moves a directory entry of a root directory of the hidden area into the directory entry area and returns a cluster recorded with the meta data to release the set hidden area, and an access control unit which controls an access to the hidden area when the hidden area is set.

Claims

1. An apparatus in a file system including a File Allocation Table (FAT) area, a directory entry area, and a data area, the FAT area, the directory entry area, and the data area being separate and non-overlapping, the apparatus managing a hidden area by setting a portion of the data area as the hidden area and controlling an access to the set hidden area, the apparatus comprising:

a processor;

a hidden area generation unit, which under control of the processor, sets the portion of the data area as the hidden area and records meta data for the set hidden area in a cluster of the data area and cluster identification information for identifying a hidden area in clusters of the data area, wherein cluster numbers of the clusters are recorded in the meta data;

a hidden area release unit which moves a directory entry of a root directory of the hidden area into the directory entry area and returns the cluster recorded with the meta data and the clusters recorded with the cluster identification information to release the set hidden area; and

an access control unit which controls the access to the hidden area in a state where the hidden area is set.

2. Apparatus of claim 1, further comprising an initialization unit which judges whether a hidden area exists in a data storage medium when the data storage medium is mounted on the file system and loads meta data of the hidden area of the data storage medium into a memory when the hidden area exists in the data storage medium.

3. The apparatus of claim 2, further comprising a hidden area judgment unit which judges whether the hidden area of the data storage medium exists, with a signature included in the meta data of the hidden area of the data storage medium.

4. The apparatus of claim 1, further comprising a hidden area allocation unit which additionally allocates a hidden area when all hidden areas currently allocated are used.

5. The apparatus of claim 1, wherein the meta data comprises a first field where the cluster numbers of the clusters including cluster identification information for identifying the hidden area are recorded, and a second field where a first cluster number of a hidden root directory is recorded.

6. The apparatus of claim 5, wherein the meta data comprises at least one signature which indicates that the first field or the second field is invalid when a predetermined value is recorded and the recorded value is changed.

7. The apparatus of claim 5, wherein the hidden area release unit records the first cluster number recorded in the second field in the directory entry area.

8. The apparatus of claim 5, wherein the hidden area generation unit displays the cluster identification information in clusters, which are mapped to the cluster number recorded in the first field, by one bit for each cluster.

9. The apparatus of claim 1, wherein, the access control unit outputs a defective cluster display to an application when the hidden area is set and when the application attempts to access a hidden cluster number of the FAT area.

10. The apparatus of claim 1, wherein, the access control unit blocks the access, when an application directly accesses a hidden cluster or a hidden sector of the data area.

11. The apparatus of claim 1, wherein the access control unit permits the access, when the access is normally performed using the meta data.

12. The apparatus of claim 3, wherein the hidden area judgment unit judges that the hidden area does not exist, when the signature is not changed from a predetermined value, and when the cluster number of a first field and a second field in the meta data is included in a cluster range.

13. The apparatus of claim 1, wherein the cluster where the meta data is recorded is a last cluster of the data area.

14. The apparatus of claim 1, wherein the cluster where the meta data is recorded exists at a fixed position of the data area.

15. A method of managing a hidden area in a file system including a File Allocation Table (FAT) area, a directory entry area, and a data area the FAT area, the directory entry area, and the data area being separate and non-overlapping, the method comprising:

setting a portion of the data area as the hidden area;

recording meta data for the set hidden area in a cluster of the data area and cluster identification information for identifying a hidden area in clusters of the data area, wherein cluster numbers of the clusters are recorded in the meta data; and

controlling an access to the set hidden area using the recorded meta data in a state where the hidden area is set.

16. The method of claim 15, further comprising:

moving a directory entry of a root directory of the hidden area into the directory entry area; and

returning the cluster recorded with the meta data and the clusters recorded with the cluster identification information to release the set hidden area.

17. The method of claim 15, further comprising:

judging whether a hidden area exists in a data storage medium when the data storage medium is mounted on the file system; and

loading meta data of the data storage medium into a memory when the hidden area exists within the data storage medium.

18. The method of claim 17, wherein the judging whether the hidden area exists is performed with a signature included in the meta data of the hidden area of the data storage medium.

19. The method of claim 15, further comprising, additionally allocating a hidden area, when all hidden areas currently allocated are used.

20. The method of claim 15, wherein the meta data comprises a first field where the cluster numbers of the clusters including cluster identification information for identifying the hidden area are recorded, and a second field where a first cluster number of a hidden root directory is recorded.

21. The method of claim 20, wherein the meta data comprises at least one signature indicating that the first field or the second field is invalid when a predetermined value is recorded and the recorded value is changed.

22. The method of claim 16, wherein the moving the directory entry of the root directory of the hidden area comprises recording a directory entry of subdirectories or files of the root directory of the hidden area in the directory entry area.

23. The method of claim 15, wherein the controlling the access to the set hidden area comprises outputting defective cluster display to the application, when an application attempts to access a hidden cluster number of the FAT area.

24. The method of claim 15, wherein the controlling the access to the set hidden area comprises blocking the access, when an application directly accesses a hidden cluster or a hidden sector of the data area.

25. The method of claim 15, wherein the controlling the access to the set hidden area comprises permitting the access, when an access is normally performed using the meta data.

26. The method of claim 17, wherein the judging whether a hidden area exists in the data storage medium comprises determining that the hidden area does not exist, when the signature is not changed from the predetermined value, and when the cluster number of a first field and a second field in the meta data is included in a cluster range.

27. The method of claim 15, wherein the cluster where the meta data is recorded is a last cluster of the data area.

28. The method of claim 15, wherein the cluster where the meta data is recorded exists at a fixed position of the data area.